Actuating mechanisms for small arms

ABSTRACT

A self-loading firearm for firing rubber bullets and the like has an actuating mechanism comprising a toggle linkage which is straightened on operation of the trigger against its spring bias. Initial straightening of the toggle linkage moves the breech block forward to locate a round of ammunition in a short socket at the chamber end of the barrel. As the toggle linkage moves over center it locks the breech block forward and displaces a sear to release the firing pin. The round is fired with its case virtually unsupported. On release of the trigger the toggle mechanism is bent so withdrawing the breech block and the spent round which is automatically ejected. The firing pin is simultaneously re-cocked. Rotary and vertical stacking rechargeable magazines are described, from which a fresh round is automatically fed to the breech on ejection of a spent round.

This invention relates to firearms, and in particular to an actuatingmechanism for a firearm. The invention is especially but not exclusivelyconcerned with self-loading firearms capable of firing a number ofrounds in rapid succession, and these rounds may comprise projectiles inthe form of, for example, so called "rubber bullets", grenades, or otherfragmentation devices, or gas canisters.

In conventional practice the round to be fired comprises a projectileand a cartridge case containing a quantity of explosive which can beinitiated by operation of the firearm to provide the energy necessary toeject the projectile from the barrel of the firearm with considerablevelocity. The cartridge case is conventionally rather weak mechanically,and at the time of firing it must therefore be supported by being fullyinserted into a chamber in which it fits closely to receive mechanicalsupport from the chamber wall. From this necessity it has followed thatany self-loading mechanism must be capable of first moving each round inturn laterally into alignment with the chamber, and then longitudinallythrough a relatively long stroke sufficient to achieve full insertion ofthe cartridge case into the chamber. This requirement has caused anumber of constraints on the freedom of the designer.

The present applicant has appreciated the possibility that in someinstances a round might be fired in a partially supported or asubstantially unsupported state, ie without the necessity for thecartridge case to be fully inserted into a supporting chamber. Arelatively small forward motion of the round after alignment with thebarrel may still be necessary, in order to ensure positive location ofthe round prior to firing, but the stroke can be very considerablyshorter, and this opens the possibility of a novel and considerablysimplified actuating mechanism, which is also capable of ensuring thesmall forward movement of the round which may be necessary before firingtakes place.

Conventional practice has also been that, following the initial cockingof the weapon, the energy necessary to operate a self-loading mechanismfor chambering successive rounds has been derived in each firing cyclefrom the energy release by firing the previous round. Thus, for exampleeither the re-coil energy has been harnessed for this purpose, or someof the energy present in the gases generated on firing has been used. Ithas been necessary to provide relatively complex devices for energisingthe self-loading mechanism in these ways. It is a feature of theactuating mechanism of the present invention that the cocking of thefiring pin and any longitudinal movement required of each fresh roundfed into place is energised by manual operation of the trigger mechanismitself, thus providing the possibility for considerable simplificationof design.

According to the present invention, an actuating mechanism for a firearmhaving a body and a breech comprises

a breech block slideable longitudinally relative to the body of thefirearm and having a forward breech end for engaging and pushing forwarda round of ammunition in the breech;

a firing pin slideable longitudinally relative to the body and to thebreech block;

resilient means which can be stressed by forward movement of the breechblock relative to the firing pin;

detent means engageable with the firing pin to prevent longitudinalmovement of the firing pin relative to the body of the firearm;

and a toggle mechanism comprising first and second toggle bars andforming at least a part of an operative linkage between a trigger andthe breech block;

the first toggle bar being pivotally connected at a first pivot point tothe breech block, the second toggle bar being pivotally connected at asecond pivot point to the body of the firearm said first pivot pointbeing forward of said second pivot point, and the first and secondtoggle bars being pivotally connected together at a third pivot point,the trigger being operatively linked with the toggle mechanism wherebyinitial operation of the trigger moves the third pivot point towardsalignment with the first and second pivot points so that the breechblock is moved forwards and the resilient means is stressed, and wherebyfurther operation of the trigger moves the toggle mechanism over centreto lock the breech block forward and releases the detent means.

Advantageously the detent means comprises a sear engageable in a bent inthe firing pin, and a mechanical connection is operative between thetoggle mechanism and the sear to disengage the sear from the bent afterthe toggle mechanism is moved over centre.

The mechanical connection conveniently comprises a sear release pinslideable transversely in the firing pin so that one end of the pin cancontact the sear and the other end of the pin can contact the togglemechanism, the length of the pin being such that when the togglemechanism moves over centre it pushes the pin against the sear todisengage the sear from the bent.

Advantageously, the firearm comprises a magazine from which a freshround of ammunition can be supplied to the breech on removal of the caseof a spent round.

The magazine can be a rotary magazine comprising

a magazine body defining around part of its circumference an openingthrough which a round of ammunition can be inserted or withdrawn, andaround a remaining part of its circumference defining a circumferentialrestraint through which a round cannot be inserted or withdrawn;

a carrier rotatable within the body about a carrier axis and havingradially extending portions adjacent pairs of which define positivelocations in which a round of ammunition can be accommodated oninsertion through the opening, rounds being slideable longitudinally insaid positive locations;

resilient carrier biasing means for urging the carrier to rotate in aparticular bias direction;

a guide member moveable across the opening;

said guide member having a guide surface facing against the biasdirection so that a round inserted through the opening is guided therebyinto one of said positive locations and simultaneously rotates thecarrier against its bias;

said guide member having a round-retaining surface facing towards thebias direction which can co-operate with one of the positive locationsto positively retain the first-inserted round against circumferentialand radial movement; and

restraining means for holding the guide member in a position such thatthe guide surface faces the opening whenever the carrier occupies aposition corresponding to one in which the magazine contains less roundsof ammunition than its maximum capacity, the guide member being moveableagainst the bias direction during movement of the carrier correspondingto insertion of the final round so that the first-inserted round maythen pass through the position occupied at other times by the guidemeans.

Alternatively the magazine can be of a form in which one or more rimmedrounds of ammunition may be stacked each in contact with an adjacentround the firearm comprising

resilient magazine bias means;

a breech opening through which a round of ammunition may be insertedinto the magazine, the breech opening defining transverse guide meansthrough which a round can be inserted in a direction transversely of thebarrel axis against the action of the magazine bias means, andrestraining means which are effective on subsequent forward movement ofthe inserted round to restrain the round in the breech against theaction of the magazine bias means;

a catch which can assume a locking position in which it prevents returnof a round forwardly located in the breech to a position in which it canre-enter the transverse guide means;

further guide means by which a round in the breech can be guided in adirection transversely of the barrel axis and rearwardly into themagazine against the magazine bias means on insertion of a further roundinto the breech;

the catch being effective to keep separate the rims of one round and asubsequently inserted round during the insertion of the subsequentlyinserted round, whereby the subsequently inserted round when engaged inthe breech has its rim in front of the rim of the said one round.

The invention will now be described by way of example only withreference to the accompanying drawings, of which

FIG. 1 is a side elevational view on the line I--I of FIG. 2 of a firstembodiment of firearm in accordance with the invention,

FIG. 1A shows a part of FIG. 1 to an enlarged scale

FIG. 2 is a plan view, part in section of part of the firearm shown inFIG. 1,

FIG. 3 is a sectional end elevation on the line III--III of FIG. 1A,

FIG. 4 is a sectional end elevation on the line IV--IV of FIG. 2,

FIG. 5 is a sectional part view on the line V--V of FIG. 4,

FIG. 6 is a sectional part view on the line VI--VI of FIG. 3,

FIG. 7 is a sectional part view on the line VII--VII of FIG. 3,

FIG. 8 is a side elevational view of a round of ammunition suitable foruse in the firearm of FIGS. 1 to 7,

FIG. 9 is an end elevational view of the round of ammunition shown inFIG. 8,

FIG. 10 is a sectional elevational view of a second embodiment offirearm in accordance with the invention, also intended to use rounds ofammunition of the type shown in FIGS. 8 and 9,

FIG. 10A shows a part of FIG. 10 to an enlarged scale,

FIG. 11 is a plan view, part in section, of part of the firearm of FIG.10, and

FIG. 12 is a sectional view from below of a loading catch forming partof the firearm of FIG. 10.

As shown in FIGS. 1 to 7, a self-loading firearm comprises a barrel 1, arotating magazine assembly 2, a firearm body 3 housing a breech blockand firing mechanism, a butt assembly 4 and a pistol grip 5. A trigger 6is pivoted at 7 in the base of the pistol grip 5, and is biased torotate anticlockwise about the pivot 7 by means of a double leaf spring8 stressed against the rear of the pistol grip 5. A trigger guard 9protects the trigger against accidental operation.

Pivoted at 10 to the forward upper portion of the trigger is a linkmember 11, which extends generally rearwardly from its pivot point 10.Pivotally fixed at a pivot point 12 to the rear end of the link member11 is a rearward extension of a first toggle bar 13. Toggle bar 13 ispivotally connected at its forward end by pivot 14 to a breech block 15slideable longitudinally in the body 3. Pivotally connected by a pivot16 to an intermediate point on the first toggle bar 13 is a secondtoggle bar 17 which extends rearwardly from the pivot 16, and is itselfpivoted by a pivot 18 to the body 3.

Slideable longitudinally within a channel 19 in the breech block 15 is afiring pin 20 having a hardened forward tip portion 20A, and a sidecheek 20B which can bear on a pin 21 held captive in a transverse borein the body 3. (FIG. 2)

A strong helical compression spring 22 provided with a thrust cap 23 islocated rearwardly of the firing pin 20 in the bore 19 between aretaining pin 24 and a shoulder 25 of the bore 19. A relatively weakhelical return compression spring 26 is also located in the bore 19between a forward-facing shoulder 27 on the firing pin 20 and a shoulder28 of the bore 19.

A sear 29 pivoted to the body 3 by pivot 30 is urged to turn clockwise(as viewed in FIG. 1) about the pivot 30 by a spring 31, towardsengagement with the firing pin 20. The tip of the sear 29 can engage,through a longitudinal slot 32 in the breech block 15 with a bent 33 onthe firing pin 20, to restrain the firing pin from forward movement. Asear control pin 34 of generally cylindrical form can slide in atransverse bore 35 in the firing pin 20. The pin 34 has a flat 36 formedon its lower portion, but not extending to its lower end. The width ofthe pin 34 at the section of the flat 36 is such as to permit thatsection of the pin to slide along a longitudinal slot 37 in the breechblock 15 which is of a width less than the full diameter of the pin 34.The length of the flat 36 in the direction of the pin axis is such as topermit a limited sliding transverse movement along the bore 35, butescape of the pin 34 is prevented by abutment of its full diameterportions against the edges of the slot 37. During assembly, the pinenters the slot 37 through a keyhole 38 in the breech block 19, butduring normal operation of the firearm the relative movement of thefiring pin 20 and the breech block 19 is limited so that the pin 34 doesnot become aligned with the keyhole 38.

The magazine assembly 2 comprises a magazine body 40 and a spindle 41.The spindle is secured to the firearm body 3 by means of a screw 42, andthe magazine body 40 is secured to the spindle by means of a screw 43. Aspigot 44 on the body 40 locates within a corresponding socket on thebody 3 and correct alignment is ensured by an alignment pin 45 (FIG. 2)secured to the body 40 and fitting closely within a correspondingalignment recess in the body 3. Mounted for rotation on the spindle 41is a star wheel assembly comprising a forward star wheel 46 and arearward star wheel 47 locked to rotate together by means of dogs. Thestar wheels 46, 47 are of mutually similar transverse cross-section asbest seen in FIGS. 3 and 4, each comprising respectively five evenlyspaced radially-extending arms 48, 49 shaped to define a slightly lessthan semi-circular recess 50, 51 between each adjacent pairs of arms,the recesses of the two star wheels being axially aligned with oneanother. The star wheel assembly 46, 47 is urged to rotate in aclockwise direction as viewed in FIG. 3, by means of a pair of helicaltorsion spring 52, 53 mounted around the spindle 41. At their forwardend, the springs 52, 53 have tails which bear against a cross-pin 54 torestrain rotation around the spindle. At their rearward ends, thesprings 52, 53 have tails which engage in corresponding holes in theforward face of the star wheel portion 47. Thus when the star wheelassembly 46, 47 is turned anticlockwise (as viewed in FIG. 3), atorsional restoring force is provided by springs 52, 53. A certaindegree of torsion is imparted to the springs 52, 53 during assembly sothat they bias the star wheel assembly to turn clockwise as viewed inFIG. 3.

Each arm of the star wheel 47 is provided with a rearwardly projectingtail 55 which runs freely, as the star wheel rotates, in an annularrecess 56 in the adjacent end face of the body 3. As seen in FIG. 5, acatch 57 having a slotted pivotal mounting 58 in the body 3 is urgedforwardly by the action of a spring loaded plunger 59, the forwardmovement of the catch being limited by a stop pin 60. The catch 57 has ahooked portion 61 adapted, when in its forward position, to engage andrestrain an adjacent tail 55. The catch 57 also has a cam face 62engageable by the outer end of the pin 21.

A loading arm 63 is provided comprising a pair of curved arms 64, 65freely pivoted respectively on the spindle 41 just ahead of the starwheel 46, and on a boss formed on the forward portion of the star wheel47. The arms 64, 65 are linked rigidly together by a longitudinallyextending guide bar 66.

Referring particularly to FIGS. 3, 6 and 7, a floating pin 68 receivedin a longitudinal bore in the forward curved arm 64, where it is heldcaptive between the front face of the star wheel 46 and the rearwardface on the body 40. As shown, the forward end of the pin 68 is receivedin a curved depression 69 in the forward face of the body 40, and therearward end of the pin 68 is received in an annular grove 70 in theforward face of the star wheel 46. A cross pin 71 fixed by adhesive in aradial bore in the star wheel 46 extends across the groove 70 and actsas a stop to prevent the star wheel assembly 46, 47 making substantiallymore than a single revolution relative to the loading arm 63.

The pin 68 is of a greater length than the depth of the groove 70 plusthe thickness of the forward curved arm 64, so that normally the pin 68projects into the depression 69 so that the loading arm 63 is lockedstationary with the body 40, while the star wheel assembly can rotaterelative thereto, the groove 70 providing clearance for the pin 68.

A conical depression 72 is provided in the base of the groove 70,adjacent the cross pin 71. When the star wheel assembly 46, 47 hascompleted almost a full revolution relative to the body 40 from theposition illustrated, the end of the pin 68 within the groove 70 canenter the depression 72, which is of sufficient depth to enable theother end of the pin 68 to clear the depression 69. The loading arm 63can then move relative to the body 40 between limits set by an opening73 for the insertion of rounds of ammunition therein; the disengagementof the pin being facilitated by the curved shape of the depression 69.During this movement the star wheel 46 and the loading arm 63 are lockedtogether by the pin 68.

The round of ammunition for which the firearm is designed is shown inFIGS. 8 and 9. It comprises a cylindrical case 74 which contains aprojectile (not shown) such as for example a so-called rubber bullet.The round is also provided with a projecting rim 75 at its rearward end,and in the rearward face 76 there is provided a percussion cap 77 bywhich the rounds may be fired. The case is designed so as to besubstantially self-supporting, ie insertion into a supporting chamber toprevent rupture of the case when the round is fired is unnecessary.

Rounds may be inserted into the magazine through the opening 73. Entryof a fresh round is facilitated by a recessed portion 78 on the forwardface of the magazine body 40, bounded by a chamfered portion 79. Afterinsertion through the opening, a round is located in a correspondingpair of recesses 50, 51 which provide a positive location therefor inthe star wheels 46, 47. As the star wheel assembly is rotated, theforward end of the casing 74 is restrained from radially outwardmovement by a part-circular rim 80 which extends around the whole of theforward face of the body 40 with the exception of the region of theopening 73 (see FIG. 3). At the rear end, the casing is restrained fromradially outward movement by an arcuate rim 81. The casing is restrainedfrom axial movement around the whole circumference of the body exceptthe region of the opening 73 and the breech region, by a radiallyinwardly directed lip 82 behind which the rim 75 locates. In the regionof the breech, the round is restrained axially by a lip 39 on the breechblock 15. The concave surfaces of the curved arms 64, 65 of the loadingarm 63 are approximately semi-circular for a reason explainedhereinafter, the radius being approximately equal to that of the casing74.

The barrel 1 is provided at its breech end with a very short chamber inthe form of a socket portion 83 in which the forward end of a round canbe received. The socket portion 83 has a shoulder 84 which the roundcannot pass, and entry to the chamber is facilitated by a shortchamfered section 85.

In use of the firearm, any number of rounds up to five may be placed inthe magazine by successive insertion through the opening 73. As thefirst round is inserted, its entry is facilitated by the recess 78 andchamfered portion 79. The loading arm 63 is locked by the pin 68 in theposition illustrated. The loading arm hence cannot pivot to a positionwhere it hinders entry of the round. As the round is pressed inwardlyinto position the arms 64, 65 guide the round so that it moves also inan anticlockwise direction (as viewed in FIG. 3), towards alignment withthe barrel, ie towards the breech position. The casing 74 of the roundthus bears on the arms 48, 49 of the star wheels 46, 47 to move the starwheels anticlockwise (as viewed in FIG. 3), against the torsional biasof the springs 53, 54 until the round is fully received in acorresponding pair of recesses 50, 51. As the round reaches the positionwhere it is aligned with the barrel 1 the hook 61 of the catch 57, underthe action of the spring-loaded plunger 59, snaps into place behind thetail 55 of an arm 49. The star wheel assembly is hence held in thisposition against the bias of the springs 53, 54 by a ratchet action ofthe catch 57, with the round in the breech aligned with the barrel.

A second, third and fourth round may be inserted in exactly the mannerdescribed above. As the rounds move around the magazine they arerestrained inwardly in the recesses 50, 51 of the star wheels 46, 47 andoutwardly by rims 80, 81 whilst longitudinal movement of the rounds isrestrained by lips 39 and 82 engaging rims 75.

However, when it is desired to insert a fifth round, the loading armobstructs the path of the first round. This difficulty is overcome asfollows. As the fifth round is inserted, the star wheel 46 moves to theposition in which the recess 72 comes into alignment with the pin 68. Asthe first round pushes against the loading arm, the pin 68 is urged bythe camming action of the curved surface of the depression 69 to moveinto recess 72, so that the loading arm becomes simultaneously unlockedfrom the magazine body 40, and locked instead with the star wheel 46.Hence as the action of inserting the fifth round continues, the firstround moves round into the opening 73. However, the first round isprevented from escaping through the opening 73 by the loading arm 63locked to the star wheel 46 so that the semi-circular recesses 50, 51together with those of the arms 64, 65, enclose the round over aboutthree-quarters of its circumference.

When the trigger 6 is pulled with the magazine 2 loaded, the action isas follows. The link member 11 is moved rearwards and is hence forced topivot anticlockwise (as viewed in FIG. 1). The pivot 12 is thus forcedto move upwards, so that the toggle mechanism comprising the firsttoggle bar 13 and the second toggle bar 17 begins to straighten. Thebreech block 15 is hence moved forward by virtue of the pivotalconnection 14, carrying with it a round positively engaged behind thelip 39. As the breech block moves forward, the round slideslongitudinally through its recesses 50, 51 to located in the socket 83in the barrel 1.

As the breech block moves forward, the firing pin 20 is held on the sear29, so that the spring 22 becomes compressed between the firing pin 20and the retaining pin 24. When the toggle mechanism 13, 17 reaches itsfully straighened position, the round is fully engaged in the socket 83and the breech block is safely locked against rearward movement. A smallfurther trigger movement brings the toggle mechanism to a position whereit is locked slightly over-centre with the upper surface of the secondtoggle bar 17 bearing on the pin 34 and pushing it upwards to disengagethe sear 29 from the firing pin 20. The firing pin then shoots forwardunder the action of the spring 22, until it reaches the position shownin FIG. 1, where the thrust cap 23 bears on the shoulder 25. Thereafterthe firing pin continues forward at high speed, under its own inertia,so that its hardened tip 20A strikes the percussion cap 77 to fire theround. It will be noted that the casing of the round is almost totallyunsupported at the time of firing.

As the firing pin moves forward, it compresses the return spring 26between the shoulders 27 and 28. As the firing pin approaches the firingposition, the cheek 20B contacts the pin 21 and forces it outwards by acamming action on to the side surface of the firing pin 20. The outerend of the pin 21 now projects in front of the cam face 62, but only ifthe firing pin has shot fully forward to fire the round.

As the trigger 6 is released, it returns under the action of the leafspring 8, the toggle mechanism 13, 17 is pulled down by the return ofthe link 11, and the breech block 15 is hence drawn back towards itsoriginal position, taking with it the firing pin 20, and the spent caseof the fired round which is held by the lip 39.

During this return movement the firing pin remains in a forward positionrelative to the breech block (although retracted clear of the front faceof the breech block by the spring 26). The pin 21 is thus held outwardlyduring the return movement by contact with the flank of the firing pin.As the breech block moves back, the pin 21 bears on the face 62 of thecatch 57, to pull the catch backwards and disengage the hooked portion61 from the adjacent tail 55. The star wheel assembly 46, 47 is thusfreed from the catch 57 which now moves downwardly in its slotted pivotto clear the pin 21 and snap into position ready to catch the nextsucceeding tail 55. The star wheel assembly 46, 47 is restrained fromrotation under the action of the springs 52, 53 until the spent case hascleared the socket 83 and the chamfered portion 85, and the breech blockhas cleared the star wheel 47. When this stage is reached, the starwheel assembly is freed to index forward under the action of the springs52, 53 until the catch 57 engages the next succeeding tail 55. The spentcase is thus automatically ejected through the opening 73, and the nextround (if any) in the magazine is automatically indexed around intoalignment with the breech block 15 and the socket 83 where it is readyto fire. It should be noted, however, that this sequence can occur onlyif the firing pin 20 has been released and moved forward to fire around, thus countering the possibility of a live round beingaccidentally ejected.

When the breech is fully retracted the sear 29 moves under the bias ofthe sear spring 31 into engagement once more with the bent 33 on thefiring pin.

As long as the magazine contains another round, the sequence can berepeated and all of the rounds in the magazine may thus be fired inrapid succession by repeated operation of the trigger.

If it is desired to remove rounds from the magazine without firing, thismay be achieved by manually depressing the tail (visible in FIGS. 2 and5) of the catch 57, whereupon the star wheels 46, 47 are released andthe rounds are ejected automatically in sequence in similar manner tothe ejection of rounds when spent. Further rotation of the star wheelassembly could release all torsional pre-stress in the springs 52, 53and so detract from subsequent proper functioning of the magazine feed.This is prevented by the pin 68 coming against the cross pin 71 justafter the last round is ejected.

The embodiment of the invention shown in FIGS. 10 to 12, comprises abody 101 integral with a barrel 102, a magazine casing 103, a pistongrip 104 and an adjustable butt 105. The magazine casing 103 and pistongrip 104 are formed integrally as a steel pressing, and a trigger guard106 is welded thereto. This assembly is attached under an opening in thebody 101 by a tail 107 on the pistol grip and a transverse pin 108passing through a forward projection (not shown) on the magazine casing.

The magazine casing 103 houses a wire spring 109 positioned in the baseof the casing by riveted pins 110. Carried on the top of the spring 109is a magazine platform 111 having an upper surface of semicylindricalgeneral form. The platform 111 is hollow and can accommodate thecompressed spring 109 when fully depressed into the casing 103.

An opening 112 is provided in the upper surface of the body 101 abovethe magazine casing, through which rounds of the type shown in FIGS. 8and 9 may be inserted. A groove 113 is provided in each side wall of theopening to accommodate the rim 75, the adjacent wall portions near theupper edge of the opening 112 constituting cheeks 114 between which thecylindrical casing 74 of a round may pass, but the rim portion 75 maynot. Below the cheeks 114, the opening widens to permit entry of a rim75. At the forward end of the opening 112, the rearward end of thebarrel 102 has an upper overhanging portion 115 beneath which theforward end of a round may be held, and a lower chamfered portion 116which can guide a round downwards and rearwards into the magazine casing103. The rearward end of the barrel also has a socket 117 constituting ashort chamber into which the forward end of the casing 74 may be engagedprior to firing.

A loading catch 118 is pivoted at 119 in the steel pressing 103, 104 andis biased clockwise (as viewed in FIG. 10) by a spring 120. The loadingcatch 118 has a pair of limbs 121 which extend forwards into the opening112, a pair of limbs 122 which extend rearwardly, and is provided withan arcuate depression 123 in its upper surface.

The rear portion of the body 101 is of generally cylindrical form, and acylindrical portion of the adjustable butt 105 is slideablelongitudinally therein so that the butt length may readily be adjustedto suit the user. The adjustable butt may be locked in a desiredposition by insertion of the butt locking pin 124 through holes providedin the body 101 and the butt 105.

Slideable longitudinally in the body 101 in front of the butt 105 is abreech block 125 of generally cylindrical form. Slideable longitudinallywithin respective bores 126 and 127 in the breech block 125 are a firingpin 128 and a sear block 129. The firing pin can be biased forwardlyrelative to the breech block by a firing pin spring 130 having a thrustwasher 131 at its forward end. The forward movement of the spring 130 islimited by the washer 131 coming into contact with a shoulder 133 in thebore 126. The spring 130 is held within the bore 126 at its rearward endby a cross pin 132 located at the rear end of the breech block. Arelatively weak firing pin return spring 134 acts between a shoulder 135and the bore 126 and a shoulder 136 on the firing pin 128, to urge thefiring pin rearwards.

The sear block 129 is urged forward by a sear spring 137 whose rearwardend also reacts against the cross pin 132. Pivoted on a transverse searpivot 138 within a longitudinal slot in the sear block 129 is a sear139. The sear has a bent on its upper edge which engages with atransverse pin 140 located in the body 101. The sear also has a nosewhich can engage with a bent 141 in the firing pin 128. A sear pin 142is slideable vertically in a bore which passes through the firing pinbeneath the sear bent. The sear pin 142 is of generally cylindricalform, but has a reduced diameter portion 143 which can slidelongitudinally within a longitudinal slot 144 in the breech block 125.During assembly, the pin 142 can enter the slot 144 through a keyhole145, but cannot escape therefrom during normal operation of the firearm.The pin can move vertically between limits determined by the length ofthe reduced diameter portion and the depth of the slot 144.

Pivoted to the breech block 125 at 146 is a first toggle bar 147.Pivoted to the body 101 at 148 is a second toggle bar 149. The first andsecond toggle bars are pivoted to each other at 150 to constitute atoggle mechanism, which is biased downwardly by a toggle spring 151.

A trigger 152 is pivoted at 153 to the pistol grip 104, the pivot beingretained by spring clip 154. The upper surface of the trigger is formedin the shape of a V, and the lower surface of the second toggle barbears on the rearward "arm" of the V.

A pin 155 has an enlarged head 156 by which it is held captive in astepped bore 157 in the breech block 125, which bore 157 is angledforwardly and down from the bore 126 through to the exterior of thebreech block. The pin 155 is prevented from escaping upwardly andrearwardly from the bore 157 by contact with the underside of the firingpin 128. When the firing pin is in a rearward position relative to thebreech block 125, the head 156 thereof can retract into a cam slot 158in the forward underside of the firing pin, so that the lower end of thepin 155 can retract into the breech block. As the firing pin nears itsmost forward position relative to the breech block, an arcuate portionof the cam slot 158 pushes the pin 155 downwards so that it projectsfrom the breech block.

As shown in FIG. 11, a floating extractor 159 has an open slot 160therein by which it is held by means of a transverse pin 161 fixed inthe breech block 125. The extractor 159 can slide longitudinallyrelative to the breech block in a groove 162 in the body 101 and agroove 163 in the side of the breech block, and can also pivot on thepin 161 to an extent permitted by the space available between thegrooves 162 and 163. The extractor is urged forwardly by an extractorspring 164 engaged in a recess 165 in the breech block and actingthrough a plunger 166. The plunger 166 bears on a flat rear face of theextractor, which is so angled that the forward end of the extractor isbiased towards a position somewhat inwards from the groove 162. Theextractor 159 has an inwardly-directed hook 167 at its forward end and asmall inwardly-directed projection 168 at its rearward end. A short pin169 fixed in the body 101 projects into the groove 162 to obstructmovement of the extractor forwards therein beyond the pin.

A pin 170 is slideable transversely in a bore in the breech block whichopens into the bore 126 and the groove 163. When the firing pin occupiesa forward position relative to the breech block, the inner end of thepin 170 bears on the flank of the firing pin, so that the outer end ofthe pin 170 is forced to project into the groove 163. When the firingpin occupies a rearward position relative to the breech block, a recess171 in the flank of the firing pin comes opposite the pin 170 so that itcan retract from the groove 163.

The firearm is loaded by inserting a rimmed round of the type shown inFIGS. 8 and 9 in through the aperture 112, with the rim passing downthrough the grooves 113 and the forward end of the round passing behindthe overhanging portion 115. This action depresses the magazine platform111 and compresses the spring 109, and also as the rim 75 bears on thelimbs 121, the loading catch 118 is depressed about its pivot. As therim clears the cheeks 114, the round is given a forward movement so thatthe rim passes below the cheeks, and the forward end of the round passesunder the overhanging portion 115. This frees the limbs 121 from underthe rim 75 so that the loading arm springs up behind the rear face 76 ofthe round to prevent the round being drawn back again. The round is thusheld captive under the overhang 115 and the cheeks 114, in alignmentwith the barrel 102. The round may now be fired as describedhereinafter, or alternatively a second round may be inserted in the sameway as the first.

It will be observed that when a second round is inserted through theopening 112, its rim will occupy a position behind that of the firstround. For reasons which will become more clearly apparent hereinafter,the feeding of rounds from the magazine back to the firing position inthe breech will be obstructed if the rounds are stored in the magazinewith the rim of a second-inserted round behind that of the first.Accordingly it is an important function of the loading catch 118 that itensures that the first-inserted round enters the magazine with its rimbehind that of the second.

This is achieved as follows. The second round is inserted on top of thefirst round with its rim in grooves 113. As the second round is pusheddown the first round is guided downwards and rearwards by the chamber116. At this point the rim of the second round depresses the loadingcatch 118 on to the rim of the first round, thus enabling the secondround rim to pass over the rim of the first round when pushed forwardengaging under the cheeks 114. As the second inserted round moves downand forward, the loading catch 118 snaps up behind it, locking thesecond round forward in the breech in the same way as the first. Thefirst round now occupies a position in the magazine casing with thesecond round resting on top of it and holding it down against the spring109, the rim of the second in front of that of the first.

The second round may now be fired as described hereinafter, or a thirdround may be inserted in the same way as the second. If a third round isinserted, the final position will be with the first and second rounds inthe magazine, biased upwardly by the spring 109, and the third roundresting on top of the second and holding it down. The third round willbe in the breech, its forward end under the overhanging portion 115, itsrim under the cheeks 114, and the arms 121 preventing its escaperearwards. The rim of the third round will be in front of the rim of thesecond round.

When the trigger 152 is pulled against the pistol grip 104, it pivotsrearwardly about the pivot 153. The upper surface of the trigger bearsagainst the second toggle bar 149, forcing it upwards and sostraightening the toggle mechanism comprising the toggle bars 147, 149.As the toggle mechanism straightens, the breech block 125 is pushedforwards, but the firing pin 128 is restrained from forward movement byengagement with the sear 139. As the breech block moves forwards, thespring 130 is compressed between the pin 132 and the firing pin 128, andthe spring 137 is compressed between the pin 132 and the sear block 129held on the pin 140. If there is a round in position aligned with thebarrel, forward movement of the breech block also pushes the round intopositive engagement in the socket 117, the rim of the round sliding onthe cheeks 114 against which it is held by the bias of the spring 109.As the round nears full engagement in the socket 117, the toggle bars147, 149 reach the straight position and pass slightly over centre tolock the breech block 125 positively in a forward position. At the sametime the upper surface of the first toggle bar 147 contacts the pin 142and pushes it upwards to disengage the sear 139 from the bent 141 on thefiring pin 128. The firing pin is thus freed to shoot forward at highspeed under the action of the spring 130, and strike the percussion cap77 of the round to fire it. It will be observed that in the positionillustrated the spring 130 rests on the shoulder 133 (via the washer131), but the tip of the firing pin remains within the breech block. Thefiring pin thus completes its forward movement under its own inertia,compressing the light restoring spring 134. The spring 134 then retractsthe firing pin immediately after firing, so that its tip lies within thebreech block clear of the percussion cap 77, where it cannot interferewith ejection of the spent case. When the trigger is released afterfiring, the toggle mechanism is pulled back from its over-centreposition by the spring 151, and the breech block is retracted by thespring 137 compressed between the pin 132 and the sear block 127.

The extractor claw 159 is effective only whena round is present in thebreech. At other times, the forward end of the extractor is angledinwardly under the bias action of the spring 164 on its rear face, sothat it always clears the pin 169, and simply moves back and forth inunison with the breech block 125. When the extractor 159 is thus angledinwardly, the projection 168 can clear the pin 170 even when the pin 170is fully extended by contact of its inner end with the flank of thefirin pin 128.

When a round is introduced in front of the breech block 125, however,the rim 75 thereof contacts the extractor behind the hook 167 to pushits forward end outwardly into the groove 162. In this orientation, theprojection 168 cannot clear the pin 170 when fully extended by contactof its inner end with the flank of the firing pin, and forward movementof the extractor is limited by contact with the pin 169.

When the trigger is operated with a round in position in front of thebreech block, the extractor 159 moves forward with the breech block 125until the extractor contacts the pin 169. As the breech block movesforward further, the extractor is prevented from doing so, and the pin161 slides along the slot 160 in the extractor, the rear end of theextractor bearing on the plunger 166 to compress the spring 164. At thisstage of the firing sequence, the firing pin 128 is held to the body 101by the sear 139, and hence it cannot move with the breech block. Thus asthe pin 170 comes adjacent the projection 168 the pin 170 can retractinto the recess 171 in the firing pin to clear the projection. When thefiring pin is freed from the sear, the flank of the firing pin onceagain contacts the inner end of the pin 170 to hold it locked fullyoutwards, but now the pin 170 is in front of the projection 168. As thebreech block and firing pin are retracted by the spring 137 on releaseof the trigger, the extractor is thus held to the breech block by thepin 170 engaging in front of the projection 168. Since the rim of theround is caught behind the hook 167, the spent case is withdrawn withthe breech block until it clears the cheeks 114 and comes into line withthe slots 113. The loading catch 118 is held down to permit thisextraction to occur, as explained hereinafter. When the rim clears thecheeks 114 there is no influence restraining the spent case against thebias of the spring 109, and the spent case is thus ejected automaticallythrough the opening 112. It will be appreciated that if the loadingcatch were not held down during this extraction sequence the upper andlower round are held in contact with one another by the spring 109.However, because it is held down the loading catch 118 itself in turnholds down the lower round so that the rim of the upper round can sliderearwardly and upwardly over the upper surfaces of arms 121, thusclearing the lower rim. The function of the loading catch is thus seento be an exceedingly important one. In its absence, the spent case wouldbe prevented by contact of its rim with the rim of the lower round, fromretracting fully, and hence could not be ejected.

As soon as the spent case is ejected, the forward end of the extractoris free to move inwards under the influence of the spring 164 and theplunger 166 on its rear end. The resulting small rotation of theextractor is sufficient to enable the projection 168 to clear the pin170 so that the extractor snaps back immediately (ie before the nextround can rise into the breech to obstruct the forward movement of theextractor) to its forward position relative to the breech block, asshown in FIG. 11.

In order to permit extraction of the spent case, the loading catch 118must be held down whilst the case is moved rearwards. This is achievedby the pin 155. When the breech block is moving forward to locate theround in the socket 117, the head 156 of the pin 155 can enter the camslot 158 in the firing pin, so that the pin can retract when its outerend contacts the loading catch 118. As the breech block completes itsforward movement the underside of the breech block contacts the arms 121to depress the loading catch 118, but the pin 155 plays no part in this.However, when the firing pin is released from the sear 139, the pin head156 is cammed outwardly by the rounded end of the cam slot 158, so thatby the time the firing pin strikes the percussion cap 77, the pin 155 isheld fully extended on the flank of the firing pin. In this position,with the breech block fully forward, the extended pin 155 contacts aflat upper forward surface of the catch 118 to hold the catch depressedso that the limbs 121 can pass under the rim 75 of the round beingextracted and hold down the rim of the next succeeding live round. Asthe firing sequence is completed, the breech block and firing pin arewithdrawn in unison, with the pin 155 hence still extended. Thisrearward movement first clears the breech block of contact with theloading catch 118, but the catch cannot rise again to the position shownin FIG. 10 until the breech block has withdrawn far enough for the pin155 to enter the arcuate portion 123, by which time the spent case haspassed rearwardly clear of the arms 121. It will be seen that thearrangement described has the great advantage of countering thepossibility that a round which has not been fired will be accidentallyejected.

When the spent case is ejected, if there is no further round present inthe magazine, the magazine platform rises under the influence of thespring 109 until restrained by contact with the overhanging portion 115.If, however, a further round is present it is urged upwardly by thespring 109. As it moves upwards, it is guided forwardly by curvedunder-surfaces of the limbs 121 of the loading catch 118, and at itsforward end on the chamfered surface 116. The next round thus moves upin front of the loading catch 118 so that it is held captive by thecheeks 114 and the overhanging portion 115. A further firing sequencecan then be initiated immediately by operation of the trigger, oralternatively the magazine can be re-filled by insertion of one or morerounds through the opening 112.

We claim:
 1. A firearm having a body, a breech and an actuatingmechanism, said firearm comprising:a breech block slideablelongitudinally relative to the body of the firearm and having a forwardbreech end for engaging and pushing forward a round of ammunition in thebreech; a firing pin slideable longitudinally relative to the body andto the breech block; resilient means which can be stressed by forwardmovement of the breech block relative to the firing pin; detent meansengageable with the firing pin to prevent longitudinal movement of thefiring pin relative to the body of the firearm; and a toggle mechanismcomprising first and second toggle bars and forming at least a part ofan operative linkage between a trigger and the breech block; the firsttoggle bar being pivotally connected at a first pivot point to thebreech block, the second toggle bar being pivotally connected at asecond pivot point to the body of the firearm, said first pivot pointbeing forward of said second pivot point, and the first and secondtoggle bars being pivotally connected together at a third ivot point,the trigger being operatively linked with the toggle mechanism wherebyinitial operation of the trigger moves the third pivot point towardsalignment with the first and second pivot points so that the breechblock is moved forwards and the resilient means is stressed, and wherebyfurther operation of the trigger moves the toggle mechanism over centerto lock the breech block forward and releases the detent means, andwherein said detent means includes a sear engageable in a bent in thefiring pin, and a mechanical connection operative between the togglemechanism and the sear to disengage the sear from the bent after thetoggle mechanism is moved over center, said mechanical connectionincluding a sear release pin slideable transversely in the firing pin sothat one end of the pin can contact the sear and the other end of thepin can contact the toggle mechanism, the length of the pin being suchthat when the toggle mechanism moves over center, it pushes the pinagainst the sear to disengage the sear from the bent.
 2. A firearmaccording to claim 1 further comprising a magazine from which a freshround of ammunition can be supplied to the breech on removal of the caseof a spent round.
 3. A firearm according to claim 2 wherein the magazineis a rotary magazine comprisinga magazine body defining around part ofits circumference an opening, through which a round of ammunition can beinserted or withdrawn, and around a remaining part of its circumferencedefining a circumferential restraint through which a round cannot beinserted or withdrawn; a carrier rotatable within the body about acarries axis and having radially extending portions adjacent pairs ofwhich define positive locations in which a round of ammunition can beaccommodated on insertion through the opening, rounds being slideablelongitudinally in said positive locations; resilient carrier biasingmeans for urging the carrier to rotate in a particular bias direction; aguide member moveable across the opening; said guide member having aguide surface facing against the bias direction so that a round insertedthrough the opening is guided thereby into one of said positivelocations and simultaneously rotates the carrier against its bias; saidguide member having a round-retaining surface facing towards the biasdirection which can co-operate with one of the positive locations topositively retain the first-inserted round against circumferential andradial movement; and restraining means for holding the guide member in aposition such that the guide surface faces the opening whenever thecarrier occupies a position corresponding to one in which the magazinecontains less rounds of ammunition than its maximum capacity, the guidemember being moveable against the bias direction during movement of thecarrier corresponding to insertion of the final round so that thefirst-inserted round may then pass through the position occupied atother times by the guide means.
 4. A firearm according to claim 2wherein the magazine is of a form in which one or more rimmed rounds ofammunition may be stacked each in contact with an adjacent round thefirearm comprisingresilient magazine bias means; a breech openingthrough which a round of ammunition may be inserted into the magazine,the breech opening defining transverse guide means through which a roundcan be inserted in a direction transversely of the barrel axis againstthe action of the magazine bias means, and restraining means, which areeffective on subsequent forward movement of the inserted round torestrain the round in the breech against the action of the magazine biasmeans; a catch which can assume a locking position in which it preventsreturn of a round forwardly located in the breech to a position in whichit can re-enter the transverse guide means; further guide means by whicha round in the breech can be guided in a direction transversely of thebarrel axis and rearwardly into the magazine against the magazine biasmeans on insertion of a further round into the breech; the catch beingeffective to keep separate the rims of one round and a subsequentlyinserted round during the insertion of the subsequently inserted round,whereby the subsequently inserted round when engaged in the breech hasits rim in front of the rim of the said one round.
 5. A firearmaccording to claim 1, wherein the toggle mechanism moves the breechblock longitudinally forward through a distance sufficient to ensure nomore than a partial insertion of the round of ammunition into a locatingsocket, whereby the casing of the round is substantially unsupported atthe time of firing.